patch 9.1.0492: filetype: Vim-script files not detected by shebang line

Problem:  Vim-script files may not be recognised
Solution: Add shebang line detection (Doug Kearns)

closes: #15012

Signed-off-by: Doug Kearns <dougkearns@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

runtime/autoload/dist/script.vim

@@ -229,6 +229,10 @@ export def Exe2filetype(name: string, line1: string): string
   elseif name =~ '^execlineb\>'
     return 'execline'
 
+    # Vim
+  elseif name =~ '^vim\>'
+    return 'vim'
+
   endif
 
   return ''